The invention relates to a power steering system, in particular an electric auxiliary power steering system for a vehicle, comprising a rotating component driven by a servomotor.
DE 103 10 492 A1 shows and describes an electric power steering system, wherein a servomotor drives an axially shifting element, the ball screw of which engages with a female thread of an axially fixed nut held in a frame. The nut and a belt pulley of a traction gear are non-rotatably fixed between the servomotor and the moving screw so formed. The nut is supported and mounted at the frame by way of a radial fixed bearing. The radial bearing is designed as a rolling bearing and in particular is designed as a four-point bearing since axial forces in particular must also be absorbed.
The extent of play of the four-point bearing and the chatter of the bearing caused by rapidly changing axial forces on the bearing races and rolling elements during operation of the power steering system are reduced through suitable measures.
In power steering systems, there are also known rotating components, which are supported by rolling bearings, wherein the rolling bearing must absorb axial forces, such as in the support of a steering nut of a steering column gear.
However, the rapidly changing axial forces that act on the bearing races of a rolling bearing of this kind, that occur during the operation of such power steering systems cause changes in the amount of play in the rolling bearing, in particular due to different degree of heating of the bearing races of the rolling bearing at the beginning of operation of the power steering system. Under some circumstances, these changes in play can cause occasional chatter at the beginning of operation of a power steering system, until the operational play specified by design is ultimately established as a result of even heating of the components of the rolling bearing. At low operating temperatures, the bearing play is detrimental to bearing friction.
The known roller bearing designs are not always able to prevent noise during this operational phase in the special application of a power steering system.